Partial sums of sequence A001221 (number of distinct primes dividing n).

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =6a(6) =7a(7) =8a(8) =9a(9) =11a(10) =12a(11) =14a(12) =15a(13) =17a(14) =19a(15) =20a(16) =21a(17) =23a(18) =24a(19) =26a(20) =28a(21) =30a(22) =31a(23) =33a(24) =34a(25) =36a(26) =37a(27) =39a(28) =40a(29) =43